“The addition of Medivation will strengthen Pfizer’s Innovative Health business and accelerate its pathway to a leadership position in oncology, one of our key focus areas, which we believe will drive greater growth and scale of that business over the long-term.

“This transaction is another example of how we are effectively deploying our capital to generate attractive returns and create shareholder value.”

David Hung, founder, president and CEO of Medivation, said: “We believe the combination with Pfizer is the right next step in our growth trajectory and is a testament to the passion and dedication by which the Medivation team has delivered on our mission to profoundly transform patients’ lives through medically innovative therapies.

“This compelling transaction will deliver significant and immediate value to our stockholders and provides new opportunities for our employees as part of a larger company.

“We believe that Pfizer is the ideal partner to extend the reach of our blockbuster Xtandi franchise and take our promising, late-stage assets – talazoparib and pidiluzimab – to their next stages of development so that they can be made available to patients as quickly as possible.”

“The price paid is higher than Sanofi’s $10 billion bid, but less than the $17 billion Pfizer paid for Hospira in 2015.

“Pfizer management will be pleased to have landed a prize asset following several high profile failed bids – AstraZeneca in 2014, Pharmacyclics in 2015 and Allergan in 2016.

“Pfizer has been playing catch up in immuno-oncology, currently the hottest area in drug development.

“The wider oncology market is worth $80 billion in annual sales and is growing at 10% per annum.

“Pfizer shareholders will question the price paid for a company which has one major drug – Xtandi for prostate cancer, and two other assets in the pipeline (breast and blood cancer).

“Although peak sales for Xtandi are forecast to hit $8 billion over the next decade, it should be noted US sales for Xtandi are shared with Japanese company Astellas.

“The long-term question for investors remains whether Pfizer has overpaid for an asset in a highly competitive and fast moving therapeutic area.

“In the meantime, Medivation shareholders will be much happier, given the company’s share price has doubled over the past six months.

“The wider concern for investors in the pharmaceutical sector surrounds under pressure CEOs, who are turning to large scale M&A and overpaying for biotech assets in order to beef up anaemic drug pipelines.”